/Engine/Plugins/Experimental/GeometryScripting/Source/GeometryScriptingCore/Public/GeometryScript/MeshSelectionFunctions.h
Create a new Mesh Selection of the SelectionType for the TargetMesh by finding all elements that have a normal vector that is within an angular deviation threshold from the given Normal. For Triangle and PolyGroup selections the triangle facet normal is used, for Vertex selections the per-vertex averaged normal is used.
static [UDynamicMesh](API\Runtime\GeometryFramework\UDynamicMesh) * SelectMeshElementsByNormalAngle ( [UDynamicMesh](API\Runtime\GeometryFramework\UDynamicMesh) * TargetMesh, [FGeometryScriptMeshSelection](API\Plugins\GeometryScriptingCore\GeometryScript\FGeometryScriptMeshSelection) & Selection, FVector Normal, double MaxAngleDeg, [EGeometryScriptMeshSelectionType](API\Plugins\GeometryScriptingCore\GeometryScript\EGeometryScriptMeshSelectionType) SelectionType, bool bInvert, int MinNumTrianglePoints )